IP城域网业务控制层BRAS可靠性设计方案探讨

BRAS作为IP城域网业务控制层管理用户及流量的核心设备,其可靠性设计是实现城域网高QoS的重要保证。在目前BRAS热备技术尚不完善的情况下,本文提出了端口聚合、分场景冷备等多种可靠性设计方案,并对各种方案的优劣势及适用场景进行了分析和探讨。     

基于池组化技术的BRAS部署方案及组网策略研究

宽带接入网络及相关业务的迅猛发展对城域网业务边缘节点提出更高要求。文章首先介绍现网BRAS的部署情况以及存在的设备可靠性低、建设成本高、设备资源利用率低、运维复杂等问题,然后提出BRAS设备的池组化组网架构,并阐述基于池组化技术的BRAS部署及组网方案的发展趋势,最后重点分析BRAS部署及组网方案不同演进阶段的关键技术(包括双机热备、虚拟集群、Pool技术及基于SDN的云化网关等)。     

宽带远程接入服务器冗余热备份技术在IP城域网中的应用

在分析徐州城域网现状的基础上,提出了解决BRAS单点故障的冗余热备份技术,对该技术的应用方案进行了详细的设计.该方案通过主备BRAS设备间信息同步及基于隧道的重定向流量引导等技术,实现了主备BRAS之间的无缝切换,即使在BRAS及其相连链路出现故障的情况下,也不会影响用户宽带业务的正常使用.     

城域数据网P2P流量优化方案

分析了P2P流量在城域数据网中的流向,并从运营商网络建设的角度,提出了P2P流量优化方案,包括BRAS节点的分布部署、IPv6地址的加速引入、分布式地址转换技术的应用和对P4P技术的关注,为运营商在智能管道时代在流量管理方面获得主动。     

新运营者城域数据网建设策略

简要介绍了目前城域数据网络发展、现状和主要组网技术,分析了新运营者城域数据网在不同阶段需要解决的主要问题,并提出初期利用MSTP方式组建城域传输和数据网,最终将城域数据网分离独立组网的发展思路。最后介绍了新运营者在南方某省会城市初期合并建设MSTP城域传输网和数据网,以及演进为独立的城域MSTP传输网、NGN轻载数据网和纯数据网。     

基于双BRAS组网建设的可探索应用

宽带接入服务器(BRAS)在IP城域网中是关键的业务控制层设备,PPPoE、IPoE、静态IP等越来越多的业务依靠统一功能的BRAS设备承载。对影响BRAS组网建设的可靠性因素进行了分析,从BRAS的设备级可靠性、网络级可靠性、业务级可靠性等方面对常用BRAS的可靠性组网方案进行探讨,结合本地城域网BRAS备份部署案例做了相应方案的对比和说明。     

广东移动基于城域传送网的数据业务承载方式探讨

通过对城域数据网的承载技术分析,从广东移动的数据业务发展定位出发．讨论了广东移动如何以城域MSTP技术的使用进行构建,实现城域数据网与城域传送网的有效结合,以满足未来几年移动公司数据业务的发展需求。     

铁路数据网网络安全边缘防护策略优化

以铁路数据网PE和CE间部署安全边缘防护后业务流量发生中断为例,对业务系统接入铁路数据网的网络架构进行分析,结合铁路数据网IS-IS协议和安全边缘策略部署的相关原理,提出基于安全边缘防护的双机热备优化方案,通过对业务接入方式进行研究,比对双机热备下主备备份和负荷分担工作模式的区别,选择主备备份工作模式,并予以实施,成功解决铁路数据网网络安全边缘防护策略部署不当,影响业务正常使用的问题。     

宽带接入服务器冗余备份方案探讨

通过对宽带接入服务器冗余备份方案的探讨,包括冷备份、热备份等方式,向运营商提供解决BRAS设备可靠性的方案,提供用户的满意度。     

城域网组播复制点位置设定分析

随着ITV业务的快速发展,城域网上单台BRAS设备承载的ITV用户数量将越来越多,BRAS下行的单播流量将极大地占用接入网带宽。组播复制点是否需要从现有的BRAS上下移到接入网设备,下移的效果如何,何时下移合适,本文针对这些问题对两种组播复制点位置设定方案进行了分析,预测和检验了下移后的效果,提出了下移的业务场景。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.